EP0105199B1 - Radiation smoke alarm - Google Patents

Radiation smoke alarm Download PDF

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Publication number
EP0105199B1
EP0105199B1 EP83108590A EP83108590A EP0105199B1 EP 0105199 B1 EP0105199 B1 EP 0105199B1 EP 83108590 A EP83108590 A EP 83108590A EP 83108590 A EP83108590 A EP 83108590A EP 0105199 B1 EP0105199 B1 EP 0105199B1
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EP
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Prior art keywords
radiation
receiver
measuring space
conductors
radiation source
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EP83108590A
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German (de)
French (fr)
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EP0105199A1 (en
Inventor
Peter Silz
Bernd Dipl.-Ing. Bartscher
Wolfram Krebs
Walter Glockmann
Engelbert Hacker
Ortwin Struss
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Heimann GmbH
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Heimann GmbH
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Priority to AT83108590T priority Critical patent/ATE35336T1/en
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
    • G08B17/107—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device for detecting light-scattering due to smoke
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
    • G08B17/113—Constructional details

Definitions

  • the invention relates to a radiation smoke detector according to the preamble of patent claim 1.
  • DE-U-7 617 247 describes a radiation smoke detector which works according to the scattered light method. It contains several diaphragms, which are intended to limit the width of the beam coming from the radiation source and bundled by a focusing element. Such a construction also results in an annoying stray light, which results from the beam limiting diaphragms, even with an optimal diaphragm condition. Therefore, according to this literature reference, a complicated arrangement of light guides tries to capture as much scattered radiation as possible from smoke particles and thus to receive a measurement signal in the presence of smoke, which differs sufficiently from the scattered radiation.
  • DE-A-2 951 459 describes a radiation smoke detector according to the preamble of claim 1, in which the beam is not delimited by diaphragms, in which scattered radiation is already largely absorbed between the light source and the focusing element, in which diaphragms continue are arranged in the measuring room, which are only intended to intercept the scattered radiation, but may not be captured by the actual beam.
  • DE-A-2 011 733 describes a device for determining the light transmission of a gas, in which two supports for a light transmitter or a light receiver are inserted into the wall of a chimney.
  • the carriers serve to hold a fiber optic that ends outside the chimney on the light transmitter or on the light receiver.
  • This document does not disclose an individually manageable device that could be used as a radiation smoke detector.
  • the object on which the present invention is based consists in the construction of a radiation smoke detector which is insensitive to environmental influences and nevertheless has a simple structure with a small proportion of the interference radiation in the measured values.
  • a property of a radiation guide known per se is used, namely that radiation only emerges at the exit surface of the light guide within a maximum exit angle to the axis of rotation of the radiation guide and that the position of the radiation source relative to the entry surface of the radiation guide only changes in the intensity distribution, but not expresses in a change in the maximum radiation angle (see also DE-A-2 011 733).
  • a change in the intensity distribution of the radiation emanating from the output surface of a radiation guide with a subsequent focusing can only lead to a change in the total intensity of the radiation, but not to an increase in the interference radiation compared to the radiation to be measured, which is reflected on the smoke particle.
  • a general change in the intensity of the radiation can, however, be easily compensated for by a corresponding change in the measuring range or the sensitivity of the receiver.
  • the radiation smoke detector according to the invention has the advantage that no electrical parts have to be present in the measuring room.
  • the light guide can be easily led out of the measuring room and only led outside to the radiation source or to the radiation receiver. This makes it possible to clean the measuring room if necessary without jeopardizing the measuring accuracy. Subsequent adjustment of the parts lying in the beam path is also not necessary, since the beam path in the measuring room is only determined by the mutual position of the light guides and the diaphragms and these can be fixed against each other without difficulty so that they are not misaligned even during a cleaning process.
  • the light guides can be immovably fixed in a common metal frame, whereby the metal frame can in turn be connected to the measuring space without difficulty.
  • the receiver is advantageously housed in a housing that is protected against electromagnetic interference and corrosion.
  • An embodiment is particularly advantageous in which the voltage source, the radiation receiver and the evaluation circuit by a common printed circuit, for. B. in the form of a film circuit, interconnected and housed in a common housing.
  • a di direct flow of scattered radiation from the radiation source to the radiation receiver is prevented by the fact that the radiation source and the radiation receiver are accommodated in separate chambers which are radiation-insulated from one another.
  • This embodiment is particularly recommended for a radiation source which generates heat at the same time, since heating of the radiation receiver can easily be avoided by a separate chamber.
  • This embodiment is advantageous, for example, when using incandescent lamps as the radiation source.
  • a particularly simple embodiment is given by using a light-emitting diode as the radiation source and a photodiode or a phototransistor as the light receiver, the radiation guides being normal light guides and by the circuit with these components, with the exception of light paths, to the corresponding end faces of the light guides with an opaque material are enveloped.
  • This covering can be, for example, a simple painting or a potting.
  • the focussing effect of the surfaces of the radiation guide is supported by the radiation guide widening conically towards the measuring space over at least part of its length. This conical widening causes a reduction in the radiation angle at the exit surface of the radiation conductor.
  • the present invention enables particularly precise beam guidance. Tolerances of the electrical components practically do not take into account the proportion of the interference signal; there is no need to select the components.
  • the positional tolerances of the components also do not need to be compensated for, as a result of which the tolerances, for example, of the diaphragms in the measuring space with respect to the beam can be kept particularly small. This makes it possible to further reduce interference reflections. Protection against corrosion and other environmental influences can in turn be easily adapted to the "Guidelines for automatic fire alarm systems, requirements and test methods for point-type smoke and heat detectors " of the Association of Property Insurers eV and DIN EN 54, Part 7, “Components of automatic fire alarm systems " .
  • shutters 22 are arranged in front of radiation conductors 23, 24.
  • the radiation conductor 23 leading to the radiation source and the radiation conductor 24 leading to the radiation receiver each have a surface 26 or 27 which is convex towards the measuring space 25 and taper from this surface in the shape of a truncated cone.
  • Both the convex surface 26 and 27 and the frustoconical configuration of the radiation guides 23, 24 act in the direction of focusing the beams 14, 15. However, since stray radiation can be emitted by the radiation guides 23, 24 up to the maximum radiation angle, an aperture 22 next to the respective light sump 11 or 12 attached.
  • Simple embodiments use visible light as radiation, an incandescent lamp or a light-emitting diode as a radiation source, a light guide as a radiation conductor and a phototransistor or a photo diode as radiation receiver.
  • visible light as radiation
  • an incandescent lamp or a light-emitting diode as a radiation source
  • a light guide as a radiation conductor
  • a phototransistor or a photo diode as radiation receiver.
  • infrared radiation or UV radiation for example, can also be used, provided appropriate focusing elements or radiation guides are available.
  • Grooves 19 and 20 and corresponding strips in holding blocks ensure shielding from disturbing side scatter radiation.
  • the radiation conductors 23, 24 are fixed in a mutual holder in their mutual position and in their position relative to the screens 8.
  • the radiation receiver can be mounted on a printed circuit without any special adjustment devices. It is located in the vicinity of the radiation exit surface of the light guide 24. A change in the position of the radiation receiver relative to the light exit surface at most causes a change in the measured intensity, but not an increase in the proportion of interference radiation, since the latter is transmitted to the same extent by the light guide to a greater or lesser extent like the radiation to be measured.

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fire-Detection Mechanisms (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Measurement Of Radiation (AREA)

Abstract

1. A radiation smoke alarm which comprises a radiation source and a radiation receiver, wherein the radiation source transmits its radiation, via a focussing element, in the form of a sharply defined beam (15) into a measuring space (25), and wherein the radiation receiver receives any change in radiation produced by smoke particles and measures the intensity thereof, and wherein the radiation receiver is connected to an analysis device which analyses the measured values, where the measuring space (25) contains diaphragms (8) which are not located in the beam path (14, 15) but intercept scattered radiation, whereby between the measuring space (25) and the receiver, there is a focussing element which laterally defines the field of vision of the receiver in a direction towards the area of the greatest intensity of the beam (15) transmitted to the measuring space (25), the two focussing elements being precisely fixed in their mutually relative positions and in relation to the diaphragms (8) contained in the measuring space (25), characterised in that the radiation source and the radiation receiver are accommodated in separate chambers insulated from one another in respect of radiation, and that the radiation source and the radiation receiver are connected to the measuring space (25) via radiation conductors (23, 24), where the radiation source and the radiation receiver are arranged in the vicinity of the corresponding end faces of the radiation conductors (23, 24) without special means for position adjustment, and where the focussing elements are formed by curved surfaces (26, 27) of the radiation conductors (23, 24) which face towards the measuring space (25), and where at least one beam defining diaphragm (22) is arranged between the radiation conductors (23, 24) and the measuring space (25).

Description

Die Erfindung betrifft einen Strahlungsrauchmelder gemäss dem Oberbegriff des Patentanspruchs 1.The invention relates to a radiation smoke detector according to the preamble of patent claim 1.

In der DE-U-7 617 247 ist ein Strahlungsrauchmelder beschrieben, der nach der Streulichtmethode arbeitet. Er enthält mehrere Blenden, die den von der Strahlungsquelle kommenden und durch ein fokussierendes Element gebündelten Strahl in seiner Breite begrenzen sollen. Ein derartiger Aufbau ergibt auch bei einer optimalen Blendenbeschaffenheit noch ein störendes Streulicht, welches von den Strahlbegrenzungsblenden herrührt. Daher wird gemäss dieser Literaturstelle durch eine komplizierte Anordnung von Lichtleitern versucht, möglichst viel Streustrahlung, die von Rauchpartikeln ausgeht, einzufangen und so ein Messsignal beim Vorhandensein von Rauch zu empfangen, welches sich ausreichend von der Streustrahlung unterscheidet.DE-U-7 617 247 describes a radiation smoke detector which works according to the scattered light method. It contains several diaphragms, which are intended to limit the width of the beam coming from the radiation source and bundled by a focusing element. Such a construction also results in an annoying stray light, which results from the beam limiting diaphragms, even with an optimal diaphragm condition. Therefore, according to this literature reference, a complicated arrangement of light guides tries to capture as much scattered radiation as possible from smoke particles and thus to receive a measurement signal in the presence of smoke, which differs sufficiently from the scattered radiation.

In der DE-A-2 951 459 ist ein Strahlungsrauchmelder gemäss dem Oberbegriff des Patentanspruchs 1 beschrieben, bei dem der Strahl nicht durch Blenden begrenzt wird, bei dem vielmehr Streustrahlung schon zwischen der Lichtquelle und dem fokussierenden Element weitgehend absorbiert wird, in der weiterhin Blenden im Messraum angeordnet sind, welche nur die Streustrahlung abfangen sollen, nicht aber vom eigentlichen Strahl erfasst werden dürfen.DE-A-2 951 459 describes a radiation smoke detector according to the preamble of claim 1, in which the beam is not delimited by diaphragms, in which scattered radiation is already largely absorbed between the light source and the focusing element, in which diaphragms continue are arranged in the measuring room, which are only intended to intercept the scattered radiation, but may not be captured by the actual beam.

Bereits eine geringfügige Verschiebung der Lichtquelle gegenüber dem fokussierenden Element bewirkt beim Stand der Technik eine Beleuchtung der in der Nähe des Strahles angeordneten Blenden und somit eine störende Streustrahlung, die von den Blenden ausgeht. Dementsprechend ist eine exakte Justierung der Strahlenquelle gegenüber den fokussierenden Elementen erforderlich. Entsprechendes gilt für die Durchlicht-Messmethode, da auch dort eine geringe seitliche Verschiebung des fokussierenden Elementes gegenüber der Lichtquelle eine gegenüber der kleinen aktiven Fläche moderner Strahlungsempfänger erhebliche Verschiebung des zu messenden Strahles ergibt, wodurch der Anteil der Störstrahlung an den Messwerten zunimmt und erhebliche Messfehler und Fehlalarme ausgelöst werden können. Der Strahlquerschnitt muss zumindest die Toleranzen der Lage und der Abmessungen der aktiven Fläche des Strahlungsempfängers mitüberdecken.Even a slight displacement of the light source with respect to the focusing element in the prior art causes the diaphragms arranged in the vicinity of the beam to be illuminated and thus a disturbing scattered radiation emanating from the diaphragms. Accordingly, an exact adjustment of the radiation source with respect to the focusing elements is required. The same applies to the transmitted light measurement method, since there too a slight lateral displacement of the focussing element relative to the light source results in a significant displacement of the beam to be measured compared to the small active area of modern radiation receivers, which increases the proportion of interfering radiation in the measured values and considerable measurement errors and False alarms can be triggered. The beam cross-section must also cover at least the tolerances of the position and the dimensions of the active area of the radiation receiver.

In der DE-A-2 011 733 ist eine Einrichtung zur Bestimmung der Lichtdurchlässigkeit eines Gases beschrieben, bei der in die Wand eines Schornsteins zwei Träger für einen Lichtsender bzw. einen Lichtempfänger eingesetzt sind. Die Träger dienen dabei zur Halterung einer Faseroptik, die ausserhalb des Schornsteins am Lichtsender bzw. am Lichtempfänger endet. Ein individuell handhabbares Gerät, das als Strahlungsrauchmelder verwendbar wäre, ist durch diese Schrift nicht bekannt.DE-A-2 011 733 describes a device for determining the light transmission of a gas, in which two supports for a light transmitter or a light receiver are inserted into the wall of a chimney. The carriers serve to hold a fiber optic that ends outside the chimney on the light transmitter or on the light receiver. This document does not disclose an individually manageable device that could be used as a radiation smoke detector.

Die Aufgabe, die der vorliegenden Erfindung zugrundeliegt, besteht im Aufbau eines gegen Umwelteinflüsse unempfindlichen und dennoch einfach aufgebauten Strahlungsrauchmelder mit geringem Anteil der Störstrahlung an den Messwerten.The object on which the present invention is based consists in the construction of a radiation smoke detector which is insensitive to environmental influences and nevertheless has a simple structure with a small proportion of the interference radiation in the measured values.

Diese Aufgabe wird bei einem Strahlungsrauchmelder gemäss Oberbegriff des Patentanspruchs 1 durch die kennzeichnenden Merkmale des Patentanspruchs 1 gelöst.This object is achieved in a radiation smoke detector according to the preamble of patent claim 1 by the characterizing features of patent claim 1.

Hier wird eine an sich bekannte Eigenschaft eines Strahlungsleiters ausgenutzt, nämlich dass an der Austrittsfläche des Lichtleiters Strahlung nur innerhalb eines maximalen Austrittswinkels zur Rotationsachse des Strahlungsleiters austritt und dass sich die Lage der Strahlungsquelle relativ zur Eintrittsfläche des Strahlungsleiters nur in einer Änderung der Intensitätsverteilung, nicht aber in einer Änderung des maximalen Abstrahlwinkels äussert (vgl. auch DE-A-2 011 733).Here, a property of a radiation guide known per se is used, namely that radiation only emerges at the exit surface of the light guide within a maximum exit angle to the axis of rotation of the radiation guide and that the position of the radiation source relative to the entry surface of the radiation guide only changes in the intensity distribution, but not expresses in a change in the maximum radiation angle (see also DE-A-2 011 733).

Eine Änderung der Intensitätsverteilung der von der Ausgangsfläche eines Strahlungsleiters ausgehenden Strahlung mit einer anschliessenden Fokussierung kann nur zu einer Änderung der Gesamtintensität der Strahlung führen, nicht aber zu einer Erhöhung der Störstrahlung im Vergleich zu der zu messenden, am Rauchteilchen reflektierten Strahlung.A change in the intensity distribution of the radiation emanating from the output surface of a radiation guide with a subsequent focusing can only lead to a change in the total intensity of the radiation, but not to an increase in the interference radiation compared to the radiation to be measured, which is reflected on the smoke particle.

Eine allgemeine Änderung der Intensität der Strahlung lässt sich jedoch sehr leicht durch eine entsprechende Änderung des Messbereichs bzw. der Empfindlichkeit des Empfängers ausgleichen.A general change in the intensity of the radiation can, however, be easily compensated for by a corresponding change in the measuring range or the sensitivity of the receiver.

Auf gesonderte, fokussierende Elemente ist bei dem erfindungsgemässen Rauchmelder verzichtet. Dies ist insbesondere für Strahlungen vorteilhaft, für die normale Linsenmaterialien nicht oder nicht ausreichend durchlässig sind.Separate, focusing elements are dispensed with in the smoke detector according to the invention. This is particularly advantageous for radiations for which normal lens materials are not or not sufficiently permeable.

Darüber hinaus hat der erfindungsgemässe Strahlungsrauchmelder den Vorteil, dass im Messraum keine elektrischen Teile vorhanden sein müssen. Der Lichtleiter kann ohne weiteres aus dem Messraum herausgeführt und erst ausserhalb zur Strahlungsquelle bzw. zum Strahlungsempfänger geführt werden. Dadurch ist es möglich, den Messraum ohne Gefahr für die Messgenauigkeit bei Bedarf zu reinigen. Auch eine nachträgliche Justierung der im Strahlengang liegenden Teile ist nicht erforderlich, da der Strahlengang im Messraum nur von der gegenseitigen Lage der Lichtleiter und der Blenden bestimmt ist und diese ohne Schwierigkeiten gegeneinander so fixiert werden können, dass sie auch bei einem Reinigungsvorgang nicht dejustiert werden. Beispielsweise können die Lichtleiter in einem gemeinsamen Metallrahmen unverrückbar fixiert werden, wobei der Metallrahmen seinerseits unschwierig mit dem Messraum unverrückbar verbunden werden kann.In addition, the radiation smoke detector according to the invention has the advantage that no electrical parts have to be present in the measuring room. The light guide can be easily led out of the measuring room and only led outside to the radiation source or to the radiation receiver. This makes it possible to clean the measuring room if necessary without jeopardizing the measuring accuracy. Subsequent adjustment of the parts lying in the beam path is also not necessary, since the beam path in the measuring room is only determined by the mutual position of the light guides and the diaphragms and these can be fixed against each other without difficulty so that they are not misaligned even during a cleaning process. For example, the light guides can be immovably fixed in a common metal frame, whereby the metal frame can in turn be connected to the measuring space without difficulty.

Der Empfänger wird vorteilhaft in einem gegen elektromagnetische Störungen und Korrosion geschützten Gehäuse untergebracht. Dabei ist eine Ausgestaltung besonders vorteilhaft, bei der die Spannungsquelle, der Strahlungsempfänger und die Auswertschaltung durch eine gemeinsame gedruckte Schaltung, z. B. in Form einer Folienschaltung, miteinander verschaltet und in einem gemeinsamen Gehäuse untergebracht sind. Ein direkter Fluss von Streustrahlung von der Strahlungsquelle zum Strahlungsempfänger wird dadurch unterbunden, dass die Strahlungsquelle und der Strahlungsempfänger in getrennten, gegeneinander strahlungsisolierten Kammern untergebracht sind. Diese Ausführungsform empfiehlt sich insbesondere bei einer Strahlungsquelle, welche gleichzeitig Wärme erzeugt, da durch eine getrennte Kammer eine Erwärmung des Strahlungsempfängers leicht vermieden werden kann. Diese Ausführungsform ist beispielsweise bei der Anwendung von Glühlampen als Strahlungsquelle vorteilhaft.The receiver is advantageously housed in a housing that is protected against electromagnetic interference and corrosion. An embodiment is particularly advantageous in which the voltage source, the radiation receiver and the evaluation circuit by a common printed circuit, for. B. in the form of a film circuit, interconnected and housed in a common housing. A di direct flow of scattered radiation from the radiation source to the radiation receiver is prevented by the fact that the radiation source and the radiation receiver are accommodated in separate chambers which are radiation-insulated from one another. This embodiment is particularly recommended for a radiation source which generates heat at the same time, since heating of the radiation receiver can easily be avoided by a separate chamber. This embodiment is advantageous, for example, when using incandescent lamps as the radiation source.

Eine besonders einfache Ausführungsform ist gegeben, indem als Strahlungsquelle eine Leuchtdiode und als Lichtempfänger eine Photodiode oder ein Phototransistor dient, wobei die Strahlungsleiter normale Lichtleiter sein können und indem die Schaltung mit diesen Bauelementen mit Ausnahme von Lichtwegen zu den entsprechenden Stirnflächen der Lichtleiter mit einem lichtundurchlässigen Material umhüllt sind. Diese Umhüllung kann beispielsweise eine einfache Lackierung oder ein Verguss sein. Diese Ausführungsform ermöglicht eine Funktionsprüfung der gesamten Schaltung vor dem Einbau.A particularly simple embodiment is given by using a light-emitting diode as the radiation source and a photodiode or a phototransistor as the light receiver, the radiation guides being normal light guides and by the circuit with these components, with the exception of light paths, to the corresponding end faces of the light guides with an opaque material are enveloped. This covering can be, for example, a simple painting or a potting. This embodiment enables a functional test of the entire circuit before installation.

Die fokussierende Wirkung der Oberflächen des Strahlungsleiters wird unterstützt, indem der Strahlungsleiter zumindest über einen Teil seiner Länge sich zum Messraum hin konisch erweitert. Diese konische Erweiterung bewirkt eine Verkleinerung'des Abstrahlwinkels an der Austrittsfläche des Strahlungsleiters.The focussing effect of the surfaces of the radiation guide is supported by the radiation guide widening conically towards the measuring space over at least part of its length. This conical widening causes a reduction in the radiation angle at the exit surface of the radiation conductor.

Die vorliegende Erfindung ermöglicht eine besonders genaue Strahlführung. Toleranzen der elektrischen Bauelemente gehen auf den Anteil des Störsignals praktisch nicht ein, auf eine Selektierung der Bauelemente kann verzichtet werden. Die Positionstoleranzen der Bauelemente brauchen ebenfalls nicht ausgeglichen zu werden, wodurch die Toleranzen beispielsweise der Blenden im Messraum gegenüber dem Strahl besonders klein gehalten werden können. Dadurch ist eine zusätzliche Verkleinerung der Störreflektionen möglich. Der Schutz vor Korrosion und anderen Umwelteinflüssen wiederum kann unschwierig den «Richtlinien für automatische Brandmeldeanlagen, Anforderungen und Prüfmethoden für punktförmige Rauch- und Wärmemelder" des Verbandes der Sachversicherer e.V. und der DIN EN 54, Teil 7, «Bestandteile automatischer Brandmel- deanlagen" angepasst werden.The present invention enables particularly precise beam guidance. Tolerances of the electrical components practically do not take into account the proportion of the interference signal; there is no need to select the components. The positional tolerances of the components also do not need to be compensated for, as a result of which the tolerances, for example, of the diaphragms in the measuring space with respect to the beam can be kept particularly small. This makes it possible to further reduce interference reflections. Protection against corrosion and other environmental influences can in turn be easily adapted to the "Guidelines for automatic fire alarm systems, requirements and test methods for point-type smoke and heat detectors " of the Association of Property Insurers eV and DIN EN 54, Part 7, "Components of automatic fire alarm systems " .

Die Erfindung ist nachfolgend anhand eines in der Zeichnung dargestellten Ausführungsbeispiels näher erläutert.The invention is explained below with reference to an embodiment shown in the drawing.

Bei dem Ausführungsbeispiel sind Blenden 22 vor Strahlungsleitern 23, 24 angeordnet. Der zur Strahlungsquelle führende Strahlungsleiter 23 und der zum Strahlungsempfänger führende Strahlungsleiter 24 haben jeweils eine zum Messraum 25 hin konvexe Oberfläche 26 bzw. 27 und verjüngen sich von dieser Oberfläche ausgehend kegelstumpfförmig. Sowohl die konvexe Oberfläche 26 bzw. 27 als auch die kegelstumpfförmige Ausbildung der Strahlungsleiter 23, 24 wirken in Richtung einer Fokussierung der Strahlenbündel 14, 15. Da jedoch Streustrahlung durch die Strahlungsleiter 23, 24 bis zum maximalen Abstrahlwinkel abgestrahlt werden kann, ist eine Blende 22 neben dem jeweiligen Lichtsumpf 11 bzw. 12 angebracht.In the exemplary embodiment, shutters 22 are arranged in front of radiation conductors 23, 24. The radiation conductor 23 leading to the radiation source and the radiation conductor 24 leading to the radiation receiver each have a surface 26 or 27 which is convex towards the measuring space 25 and taper from this surface in the shape of a truncated cone. Both the convex surface 26 and 27 and the frustoconical configuration of the radiation guides 23, 24 act in the direction of focusing the beams 14, 15. However, since stray radiation can be emitted by the radiation guides 23, 24 up to the maximum radiation angle, an aperture 22 next to the respective light sump 11 or 12 attached.

Einfache Ausführungsformen verwenden als Strahlung sichtbares Licht, als Strahlungsquelle eine Glühlampe oder eine Leuchtdiode, als Strahlungsleiter einen Lichtleiter und als Strahlungsempfänger einen Phototransistor oder eine Photo- diode. Daneben kann auch beispielsweise Infrarotstrahlung oder UV-Strahlung eingesetzt werden, sofern entsprechende fokussierende Elemente bzw. Strahlungsleiter zur Verfügung stehen.Simple embodiments use visible light as radiation, an incandescent lamp or a light-emitting diode as a radiation source, a light guide as a radiation conductor and a phototransistor or a photo diode as radiation receiver. In addition, infrared radiation or UV radiation, for example, can also be used, provided appropriate focusing elements or radiation guides are available.

Nuten 19 und 20 und entsprechende Leisten in Halteblöcken gewährleisten eine Abschirmung von störender seitlicher Streustrahlung.Grooves 19 and 20 and corresponding strips in holding blocks ensure shielding from disturbing side scatter radiation.

Die Strahlungsleiter 23, 24 sind in einer gemeinsamen Halterung in ihrer gegenseitigen Lage und in ihrer Lage zu den Blenden 8 fixiert. Der Strahlungsempfänger kann ohne besondere Justiervorrichtungen auf einer gedruckten Schaltung montiert werden. Er befindet sich in der Nähe der Strahlungsaustrittsfläche des Lichtleiters 24. Eine Lageveränderung des Strahlungsempfängers gegenüber der Lichtaustrittsfläche bewirkt allenfalls eine Änderung der gemessenen Intensität, nicht aber eine Erhöhung des Anteils an Störstrahlung, da letztere durch den Lichtleiter etwa im gleichen Masse stärker oder schwächer übertragen wird wie die zu messende Strahlung.The radiation conductors 23, 24 are fixed in a mutual holder in their mutual position and in their position relative to the screens 8. The radiation receiver can be mounted on a printed circuit without any special adjustment devices. It is located in the vicinity of the radiation exit surface of the light guide 24. A change in the position of the radiation receiver relative to the light exit surface at most causes a change in the measured intensity, but not an increase in the proportion of interference radiation, since the latter is transmitted to the same extent by the light guide to a greater or lesser extent like the radiation to be measured.

Claims (5)

1. A radiation smoke alarm which comprises a radiation source and a radiation receiver, wherein the radiation source transmits its radiation, via a focussing element, in the form of a sharply defined beam (15) into a measuring space (25), and wherein the radiation receiver receives any change in radiation produced by smoke particles and measures the intensity thereof, and wherein the radiation receiver is connected to an analysis device which analyses the measured values, where the measuring space (25) contains diaphragms (8) which are not located in the beam path (14,15) but intercept scattered radiation, whereby between the measuring space (25) and the receiver, there is a focussing element which laterally defines the field of vision of the receiver in a direction towards the area of the greatest intensity of the beam (15) transmitted to the measuring space (25), the two focussing elements being precisely fixed in their mutually relative positions and in relation to the diaphragms (8) contained in the measuring space (25), characterised in that the radiation source and the radiation receiver are accommodated in separate chambers insulated from one another in respect of radiation, and that the radiation source and the radiation receiver are connected to the measuring space (25) via radiation conductors (23, 24), where the radiation source and the radiation receiver are arranged in the vicinity of the corresponding end faces of the radiation conductors (23, 24) without special means for position adjustment, and where the focussing elements are formed by curved surfaces (26, 27) of the radiation conductors (23, 24) which face towards the measuring space (25), and where at least one beam defining diaphragm (22) is arranged between the radiation conductors (23, 24) and the measuring space (25).
2. A radiation smoke alarm as claimed in Claim 1, characterised in that the receiver is accommodated in a housing protected against environmental influences, in particular against electromagnetic radiation and corrosion.
3. A radiation smoke alarm as claimed in Claim 1 or 2, characterised in that the radiation source, the radiation receiver and the analysis circuit are interconnected by a common printed circuit, e.g. in the form of a foil circuit, and are accommodated in a common housing.
4. A radiation smoke alarm as claimed in one of Claims 1 to 3, characterised in that a luminescence diode is used as a radiation source and a photo-diode or photo-transistor is used as a radiation receiver, and that the circuit with these components, except for the light paths to the corresponding end faces of the light conductors, is encased by a light-impermeable material.
5. A radiation smoke alarm as claimed in Claim 1, characterised in that the radiation conductor (23, 24) widens in conical fashion towards the measuring space (25) at least along part of its length.
EP83108590A 1982-09-08 1983-08-31 Radiation smoke alarm Expired EP0105199B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83108590T ATE35336T1 (en) 1982-09-08 1983-08-31 RADIATION SMOKE DETECTOR.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823233368 DE3233368A1 (en) 1982-09-08 1982-09-08 RADIATION SMOKE DETECTORS
DE3233368 1982-09-08

Publications (2)

Publication Number Publication Date
EP0105199A1 EP0105199A1 (en) 1984-04-11
EP0105199B1 true EP0105199B1 (en) 1988-06-22

Family

ID=6172741

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83108590A Expired EP0105199B1 (en) 1982-09-08 1983-08-31 Radiation smoke alarm

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EP (1) EP0105199B1 (en)
AT (1) ATE35336T1 (en)
DE (2) DE3233368A1 (en)

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GB2270157B (en) * 1992-08-28 1996-07-24 Hochiki Co Light scattering type smoke detector
JP2648560B2 (en) * 1993-04-09 1997-09-03 ホーチキ株式会社 Scattered light smoke detector
DE4324439C2 (en) * 1993-07-21 1997-03-20 Preussag Ag Minimax smoke detector
GB9417484D0 (en) * 1993-09-07 1994-10-19 Hochiki Co Light scattering type smoke sensor
ATE247316T1 (en) * 1997-05-20 2003-08-15 Siemens Ag OPTICAL SMOKE DETECTOR
CA2236813C (en) * 1997-11-25 2005-12-27 C & K Systems, Inc. A system for absorbing and/or scattering superfluous radiation in an optical motion sensor
RU2222803C2 (en) * 2002-04-15 2004-01-27 Мешковский Игорь Касьянович System of operative diagnostics of biological contamination of air in ventilation ducts of buildings and structures
DE102008009213B4 (en) 2008-02-15 2010-09-02 Perkinelmer Optoelectronics Gmbh & Co.Kg Radiation conductor, detector, manufacturing process
EP3584774A1 (en) * 2018-06-19 2019-12-25 Wagner Group GmbH Detector for scattered light and suction fire detecting system with a detector for scattered light
US11302166B2 (en) * 2019-12-02 2022-04-12 Carrier Corporation Photo-electric smoke detector using single emitter and single receiver

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DE7617247U1 (en) * 1900-01-01 Cerberus Ag, Maennedorf, Zuerich (Schweiz)
FR1543165A (en) * 1964-05-06 1968-10-25 Optical concentrator device of a new type making it possible to obtain maximum irradiance on the sensitive element of a radiation receiver, method for determining the optimum characteristics of concentrators of this type, and implementing devices
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Also Published As

Publication number Publication date
DE3233368A1 (en) 1984-03-08
ATE35336T1 (en) 1988-07-15
EP0105199A1 (en) 1984-04-11
DE3377172D1 (en) 1988-07-28

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